1. Field of the Invention
The present invention relates to a plasma display device and a method of driving the same, and more particularly, to a method of driving a plasma display device in a reset period.
2. Description of the Related Art
A plasma display device displays characters and images using plasma generated by gas discharge. The plasma display device operates by dividing a field into a plurality of weighted subfields, and gray scales are represented by the sum of weights according to the combination of turned-on subfields. A discharge cell (hereinafter referred to as a “cell”) is initialized by a reset discharge during a reset period of each subfield, and an on-cell and an off-cell are selected during an address period of the each subfield. The on-cell is sustain discharged during a sustain period of each subfield so that images are displayed. The reset period is either a main reset period or a sub-reset period. The reset discharge is generated in all the cells during the main reset period, and is only generated in the cell having undergone the sustain discharge in the previous subfield during the sub-reset period.
Generally, the sustain period ends with a high voltage applied to a scan electrode. In the sub-reset period, a voltage at the scan electrode gradually decreases while a positive voltage is applied to a sustain electrode and a ground voltage is applied to an address electrode. When the sustain discharge is generated by the high voltage applied to the scan electrode, negative wall charges are formed on the scan electrode and more positive wall charges are formed on the sustain electrode than positive wall charges formed on the address electrode. Accordingly, a discharge is first generated between the scan electrode and the sustain electrode when gradually decreasing a voltage at the scan electrode, and another discharge is generated between the scan electrode and the address electrode. Then, the discharge between the scan electrode and the address electrode may not be normally generated because the discharge between the scan electrode and the sustain electrode is generated first. As a result, the wall charge states between the scan electrode and the address electrode may not be uniform in the cells.
In cells having insufficient wall charges formed between the scan electrode and the address electrode, a weak discharge may be generated in the address period, which may generate fewer wall charges, thereby generating an insufficient sustain discharge in the sustain period. On the other hand, in cells having excess wall charges formed between the scan electrode and the address electrode, a misfiring discharge for sustain discharging a turned-off cell may be generated.